Earth's Crystal Core

A difference in speed of acoustic waves traveling north-south vs. east-west through our planet has led some people to conclude that there is a giant crystal at the center of our planet.

However, there is a very simple alternative explanation that would work just as well. From observations of gas giants such as Jupiter, we can clearly see that matter form bands along the longitudes. This is almost certainly the case for rocky planets too.

The result of such bands is that there will be a difference in acoustic speed as observed. There is no need to invent exotic super-dense materials in order to explain observations. A quick look around the solar system gives us all the information we need.

Cross section of a hollow planet